We will continue to grow crystals of FeMo-co and attempt to get the crystals of sufficient size for x-ray diffraction studies. The molybdenum storage protein will be purified to homogeneity and the properties of this protein will be analyzed. An analysis of the steps involved in transfer of the Mo in the Mo storage protein will be initiated. By the use of modified extraction procedures, we will determine the amino acid sequence of the peptide in FeMo-co and determine its stoichiometry with respect to Mo. Similar extraction procedures will be used to extract FeMo-co from xanthine oxidase. We recently got all of the nif genes onto specialized transducing phage. The DNA from these phage will be used to attempt to synthesize active FeMo-co in an in vitro coupled transcription-translation system.